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<title>Hadoop YARN 2.0.4-alpha Release Notes</title>
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<h1>Hadoop YARN 2.0.4-alpha Release Notes</h1>
These release notes include new developer and user-facing incompatibilities, features, and major improvements. 
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<h2>Changes since Hadoop 2.0.3-alpha</h2>
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<li> <a href="https://issues.apache.org/jira/browse/YARN-470">YARN-470</a>.
     Major bug reported by Hitesh Shah and fixed by Siddharth Seth (nodemanager)<br>
     <b>Support a way to disable resource monitoring on the NodeManager</b><br>
     <blockquote>Currently, the memory management monitor's check is disabled when the maxMem is set to -1. However, the maxMem is also sent to the RM when the NM registers with it ( to define the max limit of allocate-able resources ). 

We need an explicit flag to disable monitoring to avoid the problems caused by the overloading of the max memory value.</blockquote></li>
<li> <a href="https://issues.apache.org/jira/browse/YARN-449">YARN-449</a>.
     Blocker bug reported by Siddharth Seth and fixed by  <br>
     <b>HBase test failures when running against Hadoop 2</b><br>
     <blockquote>Post YARN-429, unit tests for HBase continue to fail since the classpath for the MRAppMaster is not being set correctly.
Reverting YARN-129 may fix this, but I'm not sure that's the correct solution. My guess is, as Alexandro pointed out in YARN-129, maven classloader magic is messing up java.class.path.</blockquote></li>
<li> <a href="https://issues.apache.org/jira/browse/YARN-443">YARN-443</a>.
     Major improvement reported by Thomas Graves and fixed by Thomas Graves (nodemanager)<br>
     <b>allow OS scheduling priority of NM to be different than the containers it launches</b><br>
     <blockquote>It would be nice if we could have the nodemanager run at a different OS scheduling priority than the containers so that you can still communicate with the nodemanager if the containers out of control.  

On linux we could launch the nodemanager at a higher priority, but then all the containers it launches would also be at that higher priority, so we need a way for the container executor to launch them at a lower priority.

I'm not sure how this applies to windows if at all.</blockquote></li>
<li> <a href="https://issues.apache.org/jira/browse/YARN-429">YARN-429</a>.
     Blocker bug reported by Siddharth Seth and fixed by Siddharth Seth (resourcemanager)<br>
     <b>capacity-scheduler config missing from yarn-test artifact</b><br>
     <blockquote>MiniYARNCluster and MiniMRCluster are unusable by downstream projects with the 2.0.3-alpha release, since the capacity-scheduler configuration is missing from the test artifact.
hadoop-yarn-server-tests-3.0.0-SNAPSHOT-tests.jar should include the default capacity-scheduler configuration. Also, this doesn't need to be part of the default classpath - and should be moved out of the top level directory in the dist package.</blockquote></li>
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